Manually operated, trigger actuated dispensing pumps for liquid containers have been proposed in the past, a particular one having wide commercial acceptance and application being disclosed in U.S. Pat. No. 3,061,202, granted Oct. 30, 1962 to Tracy B. Tyler. This type of pump while finding wide spread commercial use is relatively expensive to manufacture being comprised of many different parts, each requiring in and of themselves relatively costly methods to manufacture and/or assemble and also being relatively complex and having relatively high cost materials associated therewith.
Other prior art patents have been granted which overcome in some measure the problem of the above cited U.S. Pat. No. 3,661,202, a particular one being U.S. Pat. No. 3,749,290, granted Oct. 31, 1973, to Lewis A. Micallef et al. This patent discloses a trigger sprayer having a deformable, hollow elastomeric tube internally supported in a body. The tube is compressively stressed on a sidewall thereof by a trigger mechanism to thereby reduce its internal volume and, as a result, liquid drawn thereinto from a container, is dispensed. The tubular member incorporates axially aligned, inlet and outlet ports in the bottom and top respectively of the device, together with associated inlet and outlet valving, the former being in the open bottom and the latter being in the upper part of the tubular member which is adapted to engage part of the sprayer body to form the valve. The Micallef et al. device uses a trigger to depress the sidewall of its tubular member which in turn, causes the inlet valve to close and the outlet valve to open to dispense liquid, the amount of liquid dispensed in a single actuation of the trigger being determined by the amount of sidewall movement or flexing. The Micallef device is an example of a low cost, collapsible container, non-aerosol dispenser.
U.S. Pat. No. 3,486,663 to F. H. Humphrey, granted on Dec. 30, 1969, discloses a dispenser comprising an elastomeric pump and check valve. The pump consists of an elastomeric member having a recessed portion adapted for sealing engagement with a supporting surface to define therewith a closed chamber. Also incorporated in the device are one or more internal partitions which form one or more compartments. Associated inlets and outlets are incorporated therein together with an ejection orifice. Liquid is drawn up into one or more of the compartments by the flexing of the outer wall of the pump by the finger or thumb and thereafter ejected by succeeding flexing actuations thereof.
Other types of sprayers are well-known to the art and come to mind when it is desired to spray liquids from a container. For example, a finger actuated plunger sprayer has long been available and widely used. The art is well developed with many dispensing devices proposed and manufactured for manual actuation, including trigger actuators.